Spatio-Temporal Analysis of Urban Heat Island Using Multisource Remote Sensing Data: A Case Study in Hangzhou, China

In this paper, the spatio-temporal variations of the urban heat island (UHI) in Hangzhou are analyzed using multisource remote sensing data. The annual human settlement index (HSI) was derived from the annual MODIS NDVI and DMSP-OLS datasets from 2000 through 2013. The spatio-temporal patterns of HSI as well as the longitudinal variations of land surface temperature (LST) versus HSI were analyzed. The surface urban heat island intensity (SUHII) was derived by fitting a linear relationship between LST and HSI and it denotes the UHI effect. The spatial variation of SUHII is consistent with the distribution of HSI. According to the district division of Hangzhou, the SUHII of northeast Hangzhou is higher than that of southwest Hangzhou, and the UHI enhancement in the most developed districts of Hangzhou city, Yuhang and Xiaoshan, is remarkable. These results suggest that Hangzhou has a strong UHI effect and that the UHI has local regional characteristics. The UHI effect enhancement is mainly due to the expansion of the urban area, urban anthropogenic activities, and heat emission of the built-up area. According to the changes in SUHII for the period from 2000 to 2013, the UHI effect is intensifying in Hangzhou and measures for reducing the SUHII needs to be taken. To our knowledge, this is the first time that the spatio-temporal variation of the UHI in Hangzhou has been quantitatively analyzed using long time series of multisource remote sensing data, which can help understand the evolution of UHI and guide urban planning and development.